The supervisor at the Westchester fire station where a black firefighter was fed spaghetti spiked with dog food called the 2004 incident “heinous” and recommended an immediate and comprehensive investigation but top officials chose not to pursue one.

A full inquiry would send a “clear message” about the Los Angeles Fire Department’s view of such incidents and would “head off any adverse public reaction or legal action,” Battalion Chief Steven J. Coleman wrote, according to confidential department records.

Coleman got written statements from the firefighters who were present at the dinner but wrote at one point that his investigation had hit a wall.

However, top officials decided against his recommendation and that of his supervisor to conduct what is known as an advocate investigation that could have included questioning of firefighters by specially trained officers.

Deputy Chief Andrew Fox, who supervises departmental discipline, concluded that the incident was a practical joke intended to humble Tennie Pierce, a 6-foot-5 firefighter who called himself “Big Dog.”

Fox recommended suspending two captains and a firefighter, writing that the captains “attempted to conceal the act” by not reporting it to Coleman.

Suspension ranging from six to 30 days were later approved by the chief.

Pierce, 51, is suing the city, contending that the October 2004 incident involving about 10 firefighters – including the white captains and a Hispanic firefighter – was racial harassment.

The Latino firefighter, who prepared Pierce’s plate, has said through his attorney that the action was not racially motivated.

Last month, the City Council approved a $2.7 million settlement of the lawsuit but it was vetoed by Mayor Antonio Villaraigosa after photographs surfaced showing Pierce engaged in crude firehouse hazing – smearing mustard and dumping water on restrained colleagues.